Conventional manholes include a lower or bottom pad, which may also be known as a bench, a barrel having a relatively constant diameter adjacent to and extending generally upward from the pad, a concentric or eccentric cone extending upwardly from the barrel, one or more adjusting rings to adjust the overall height of the manhole, and a casting frame on top of the adjusting rings to support a lid at an elevation substantially level with the surrounding pavement. The cone may also be known as a corbel, and the adjusting ring area may be referred to as a chimney. The casting frame is preferably sealed to the uppermost adjusting ring to preclude or minimize water flow into the manhole. Furthermore, one or more pipes may extend from the manhole. For example, a pipe may extend through a portion of the bench at a pipe invert, with the pipe continuing to extend from the pipe invert away from the manhole. In addition, other pipes may extend from any of the other portions of the manhole.
One problem with existing manholes is that many were made long ago, and oftentimes, were made of brick. Due to the old age of the manholes, as well as the materials used to make them, many manholes have begun to deteriorate or have damaged areas. The damaged areas create weak spots, which may allow water to infiltrate the sewer system and also lead to the eventual collapse of the manhole.
Methods exist for repairing the walls of manholes. One such method involves the use of a liner and a bladder to repair the manhole wall. The liner and bladder are placed in the manhole, and the bladder is expanded to press the liner against the manhole wall. The liner is impregnated with a resin and pressed against the manhole wall. Another method includes trawling, slinging, spraying, or otherwise applying a resinous or grout material to the manhole wall along either the full height of the manhole or along a damaged portion of the manhole. A liner and/or bladder is then positioned in the manhole and expanded against the material until the material cures.
However, in both of these instances, only the portions of the manhole along the height of the manhole are repaired. The bench is generally not repaired, and the juncture between any pipe extending through or from the manhole is also not repaired. These structures must be repaired separately, which increases the time of repair, as well as the difficulty in making the repairs. For example, each repair must wait for the curable material to cure and harden before repairing the next portion, which can greatly add to the total repair time. Furthermore, cured portions of the manhole repair may make it more difficult to repair subsequent portions of the manhole, which can also increase the time and cost for manhole repair. This also becomes an issue when one or more of the pipes extending through and/or from the manhole need repaired, as this creates additional time and resources.
Therefore, there is a need in the art for a method of repairing a manhole and pipes extending through and/or from the manhole that produces a generally monolithic repair interior covering most or all of the interior of the manhole, as well as at least a portion of the interior of any pipe. The method will allow the pipes to then be repaired from the repaired manhole with greater ease.